(multiset1, multiset2) -> {
          multiset1.addAll(multiset2);
          return multiset1;
        },
        (Multiset<E> multiset) -> ImmutableMultiset.copyFromEntries(multiset.entrySet()));
  }

  static <T extends @Nullable Object, E extends @Nullable Object, M extends Multiset<E>>
      Collector<T, ?, M> toMultiset(
          Function<? super T, E> elementFunction,

      Multiset<E> multiset, ObjectOutputStream stream) throws IOException {
    int entryCount = multiset.entrySet().size();
    stream.writeInt(entryCount);
    for (Multiset.Entry<E> entry : multiset.entrySet()) {
      stream.writeObject(entry.getElement());
      stream.writeInt(entry.getCount());
    }
  }

  /**

      Multiset<E> multiset, ObjectOutputStream stream) throws IOException {
    int entryCount = multiset.entrySet().size();
    stream.writeInt(entryCount);
    for (Multiset.Entry<E> entry : multiset.entrySet()) {
      stream.writeObject(entry.getElement());
      stream.writeInt(entry.getCount());
    }
  }

  /**

  }

  // Required Implementations

  /**
   * {@inheritDoc}
   *
   * <p>Invoking {@link Multiset.Entry#getCount} on an entry in the returned set always returns the
   * current count of that element in the multiset, as opposed to the count at the time the entry
   * was retrieved.
   */
  @Override
  public Set<Multiset.Entry<E>> entrySet() {
    return super.entrySet();
  }

  @Override
  Iterator<E> elementIterator() {

import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Objects;
import com.google.common.base.Preconditions;
import com.google.common.collect.Multiset.Entry;
import com.google.common.collect.Multisets.AbstractEntry;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.util.Arrays;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

    }

    @Override
    public int size() {
      return ImmutableMultimap.this.size();
    }

    @Override
    Multiset.Entry<K> getEntry(int index) {
      Map.Entry<K, ? extends Collection<V>> entry = map.entrySet().asList().get(index);
      return Multisets.immutableEntry(entry.getKey(), entry.getValue().size());
    }

    @Override
    boolean isPartialView() {
      return true;
    }

    }

    @Override
    Iterator<Multiset.Entry<K>> entryIterator() {
      return new TransformedIterator<Map.Entry<K, Collection<V>>, Multiset.Entry<K>>(
          multimap.asMap().entrySet().iterator()) {
        @Override
        Multiset.Entry<K> transform(final Map.Entry<K, Collection<V>> backingEntry) {
          return new Multisets.AbstractEntry<K>() {
            @Override

@GwtCompatible
public enum MultisetFeature implements Feature<Multiset> {
  /**
   * Indicates that elements from {@code Multiset.entrySet()} update to reflect changes in the
   * backing multiset.
   */
  ENTRIES_ARE_VIEWS;

  @Override
  public Set<Feature<? super Multiset>> getImpliedFeatures() {
    return emptySet();
  }

  @Retention(RetentionPolicy.RUNTIME)
  @Inherited

import com.google.common.collect.testing.features.CollectionSize;
import com.google.common.testing.EqualsTester;
import org.junit.Ignore;

/**
 * Tests for {@code Multiset.equals} and {@code Multiset.hashCode}.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
@Ignore // Affects only Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
@SuppressWarnings("JUnit4ClassUsedInJUnit3")

  public void testCreation_noArgs() {
    Multiset<String> multiset = ImmutableMultiset.of();
    assertTrue(multiset.isEmpty());
  }

  public void testCreation_oneElement() {
    Multiset<String> multiset = ImmutableMultiset.of("a");
    assertEquals(HashMultiset.create(asList("a")), multiset);
  }

  public void testCreation_twoElements() {
    Multiset<String> multiset = ImmutableMultiset.of("a", "b");